Thanks Sylvain!
--
Samuel K. Gutierrez
Los Alamos National Laboratory
On Jun 9, 2010, at 9:58 AM, Sylvain Jeaugey wrote:
As stated at the conf call, I did some performance testing on a 32
cores node.
So, here is graph showing 500 timings of an allreduce operation
(repeated 15,000 times for good timing) with sysv, mmap on /dev/shm
and mmap on /tmp.
What is shows :
- sysv has the better performance ;
- having the mmap file in /dev/shm is very close to sysv. We only
have +0.1 us for a complete allreduce operation, but it seems
stable. The noise is identical to sysv (must be OS noise) ;
- having the mmap file in /tmp (ext3) decreases performance (+0.4 us
compared to /dev/shm) and seems prone to some "other" noise.
Warning : the graph does not start at 0.
Sylvain
On Tue, 27 Apr 2010, Samuel K. Gutierrez wrote:
Hi,
With Jeff and Ralph's help, I have completed a System V shared
memory component for Open MPI. I have conducted some preliminary
tests on our systems, but would like to get test results from a
broader audience.
As it stands, mmap is the defaul, but System V shared memory can be
activated using: -mca mpi_common_sm sysv
Repository:
http://bitbucket.org/samuelkgutierrez/ompi_sysv_sm
Input is greatly appreciated!
--
Samuel K. Gutierrez
Los Alamos National Laboratory
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